Left-hander Hector Santiago, demoted to the bullpen on May 9 and then to triple-A Salt Lake on May 21, will be called up to start against the A’s.

Scioscia said that Skaggs, who is 4-4 with a 4.34 earned-run average in 12 starts, did not injure himself on any particular play last Thursday night in Houston, a game in which Skaggs allowed four runs and seven hits in five innings of an 8-5 loss.

“He felt it a little bit after his start — he came out a little sore,” Scioscia said. “We’re doing this more as a precaution to make sure he gets it behind him. We don’t anticipate him being out for more than two weeks, but hamstring injuries can take on a life of their own.”

Santiago, who along with Skaggs was acquired by the Angels in last December’s three-team Mark Trumbo trade, opened the season as the No. 3 starter but went 0-6 with a 5.19 ERA in seven games, striking out 31, walking 18 and allowing six home runs in 37 1/3 innings.

The Angels moved Santiago to the bullpen, where he made only two appearances in 10 days, and then to Salt Lake, where he could remain stretched out as a starter. Santiago went 1-1 with a 6.43 ERA in three games with the Bees, striking out nine and walking seven in 14 innings.